1. Field of the Invention
This invention relates in general to railroad cars and, more particularly, to a railroad passenger walk-over seat having energy dissipation means during abrupt deceleration causing seat back impact by a passenger.
2. Summary of the Prior Art
It is common in railroad passenger cars to provide seat backs capable of being walked over or moved to face in opposite directions. There exists significant problems in the past when a passenger impacted the unrestrained seat back in front of him during rapid deceleration situations, causing catastrophic emergencies. As a result, seat backs were provided in the prior art with locking mechanisms by which the seat back was restrained when a passenger collided with the seat back in front of him. A restrained seat back, however, creates an unyielding wall-like object against which the individual would be subjected to severe deceleration during emergency situations. A one hundred and fifty pound individual, for example, could be subject to in excess of 7 g's deceleration under such situations.
In the prior art, attempts were made to install energy absorbing devices in the seat back to lessen impact by increasing the distance and/or time in which an individual is subjected to deceleration forces. One technique of energy absorption is disclosed in U.S. Pat. No. 5,149,171 to Gilevich, et al. in which a latching mechanism restrains walkover movement of the seat back in a progressive manner when impacted under deceleration forces. The technique in Gilevich, et al., however, relies on a complex and cumbersome system using a pendulum and a series of gears. The latching system of Gilevich, et al. is expensive to manufacture, difficult to service, inspect and maintain, and does not demonstrate optimum impact absorption:
Another seat locking mechanism for walk-over seats is disclosed in U.S. Pat. No. 5,362,124 to Schlidt. During rapid deceleration through impact in Schlidt, a wear surface contacts a braking surface in conjunction with an energy absorption means in the form of spring blocks and Belleville washers. Like the Gilevich, et al. system, the Schlidt locking mechanism is complex, difficult to service and is not optimally capable of alleviating serious injury to the impacting passenger. Moreover, the prior systems, such as disclosed in the foregoing Gilevich, et al. and Schlidt patents, are particularly designed for the presence of two passengers on the seat rather than a single passenger. In the case of a single passenger, the impact absorption capability of prior art walk-over seats is generally ineffective and is not sufficiently responsive to deceleration forces on a single individual. Accordingly, it is desirable in the transportation industry to provide a safer, a more economical and less complex walk-over passenger seat system.